A New Jersey doctor shot a former colleague to death over an alleged work dispute yesterday — then later killed himself when police stopped him on suspicion of murder.

Dr. Payman Houshmandpour, 32, was backing out of his driveway in Voorhees, NJ, headed for work at nearby Virtua Hospital when another physician, Giocondo Navek, 39, appeared behind his car.

When Houshmandpour brough the vehicle to a stop, Navek came around the driver’s side of the silver Audi and opened fire through the window, witnesses said.

“At first, I heard two gunshots a few seconds apart from each other,” said a neighbor, Ron Gorman Jr., 27. “Then four to five rapid gunshots, right in a row—just bang, bang, bang. It was really heinous.”

Houshmandpour was a medical resident working at various Virtua hospitals on medical and surgical rotations, according to a statement from the health network.

He left behind a wife and a 1-year-old daughter, neighbors said.

Navek had also worked at Virtua, but left about 18 months ago.

He blamed Houshmandpour for his dismissal from a residency program at Virtua, said Forogh Mozaffari, the mother of Navek’s longtime girlfriend, according to The Associated Press.

A neighbor Brendan Canavan, 54, saw the murder from his window.

“The shooter calmly collected himself, brushed himself off, and just walked away at a brisk pace back to his car,” said Canavan, an investment adviser.

He wrote down the license-plate number for Navek’s silver Nissan sedan and called the cops.

An officer saw the car a mile away from the scene of the shooting and pulled Navek over, according to Jason Laughlin, a spokesman for the Camden County Prosecutor’s Office.

Navek shot himself before the officer approached, Laughlin said. He was rushed to the hospital but died there.

A Virtua spokeswoman declined to comment on whether Navek’s departure was related to a dispute with Houshmandpour.

Shocked neighbors said the victim was a “nice,” “normal guy” whose murder was out of character for their quiet complex.

“It’s tragic because he is leaving behind a family,” Canavan said. “Nothing like this happens here. This is a very well-to-do little town.”